Neotropical Sylvatic Mosquitoes and Aedes aegypti Are Not Competent to Transmit 17DD Attenuated Yellow Fever Virus from Vaccinated Viremic New World Non-Human Primates.

Beside humans, thousands of non-human primates (NHPs) died during the recent outbreak caused by the yellow fever virus (YFV) in Brazil. Vaccination of NHPs against YFV with the YF 17DD attenuated virus has emerged as a public health strategy, as it would reduce sylvatic transmission while also preserving endangered susceptible species. The hypothesis of establishing an uncontrolled transmission of this attenuated virus in nature was raised. We assessed vector competence of four sylvatic mosquito species, Haemagogus leucocelaenus, Haemagogus janthinomys/capricornii, Sabethes albiprivus, and Sabethes identicus, as well as the urban vector Aedes aegypti for YF 17DD attenuated vaccine virus when fed directly on eleven viremic lion tamarins or artificially challenged with the same virus. No infection was detected in 689 mosquitoes engorged on viremic lion tamarins whose viremia ranged from 1.05 × 103 to 6.61 × 103 FFU/mL, nor in those artificially taking ≤ 1 × 103 PFU/mL. Low viremia presented by YF 17DD-vaccinated New World NHPs combined with the low capacity and null dissemination ability in sylvatic and domestic mosquitoes of this attenuated virus suggest no risk of its transmission in nature. Thus, vaccination of captive and free-living NHPs against YFV is a safe public health strategy.

Evaluation of Two Adjuvant Formulations for an Inactivated Yellow Fever 17DD Vaccine Candidate in Mice.

The attenuated yellow fever (YF) vaccine is one of the most successful vaccines ever developed. After a single dose administration YF vaccine can induce balanced Th1/Th2 immune responses and long-lasting neutralizing antibodies. These attributes endorsed it as a model of how to properly stimulate the innate response to target protective immune responses. Despite their longstanding success, attenuated YF vaccines can cause rare fatal adverse events and are contraindicated for persons with immunosuppression, egg allergy and age < 6 months and >60 years. These drawbacks have encouraged the development of a non-live vaccine. The aim of the present study is to characterize and compare the immunological profile of two adjuvant formulations of an inactivated YF 17DD vaccine candidate. Inactivated YF vaccine formulations based on alum (Al(OH)3) or squalene (AddaVax®) were investigated by immunization of C57BL/6 mice in 3-dose or 2-dose schedules, respectively, and compared with a single dose of attenuated YF virus 17DD. Sera were analyzed by ELISA and Plaque Reduction Neutralization Test (PRNT) for detection of total IgG and neutralizing antibodies against YF virus. In addition, splenocytes were collected to evaluate cellular responses by ELISpot. Both inactivated formulations were able to induce high titers of IgG against YF, although neutralizing antibodies levels were borderline on pre-challenge samples. Analysis of IgG subtypes revealed a predominance of IgG2a associated with improved neutralizing capacity in animals immunized with the attenuated YF vaccine, and a predominance of IgG1 in groups immunized with experimental non-live formulations (alum and AddaVax®). After intracerebral (IC) challenge, attenuated and inactivated vaccine formulations showed an increase in neutralizing antibodies. The AddaVax®-based inactivated vaccine and the attenuated vaccine achieved 100% protection, and alum-based equivalent formulation achieved 70% protection.

Safety and immunogenicity of 17DD attenuated yellow fever vaccine in howler monkeys (Alouatta spp.).

BACKGROUND: Alouatta spp. are highly susceptible to yellow fever (YF) infection and develop an often fatal disease. The threat posed by an outbreak started in 2016 leads us to investigate vaccination as a potential tool in preventing YF in non-human primates (NHP). METHODS: Susceptible howler monkeys were immunized with three different concentrations of the human Brazilian commercial YF17DD vaccine. Post-vaccination viremia/RNAemia, immunogenicity, and safety were characterized. RESULTS: The vaccine did not produce YF clinical manifestations in any of the NHPs. After immunization, all animals seroconverted demonstrating the ability of the YF vaccine to induce humoral response in Alouatta species. CONCLUSIONS: The present work has demonstrated the safe and immunogenic profile of the existing YF 17DD vaccine in howler monkeys. This knowledge may support further studies with other susceptible monkey species and provide a possible solution for controlling epizootics and preventing the devastation of endangered species.

Vaccines for neglected and emerging diseases in Brazil by 2030: the "valley of death" and opportunities for RD&I in Vaccinology 4.0.

We examine the implications of the very low competitiveness of the Brazilian vaccine RD&I system, which precludes the development of all the important vaccines required by the National Immunization Program (NIP), severely impacting the healthcare of the population. In a country dramatically affected by COVID-19 pandemic and by an exponential increase in emerging and neglected diseases, particularly the poor, these RD&I constraints for vaccines become crucial governance issues. Such constraints are aggravated by a global scenario of limited commercial interest from multinational companies in vaccines for neglected and emerging diseases, which are falling into a "valley of death," with only two vaccines produced in a pipeline of 240 vaccines. We stress that these constraints in the global pipeline are a window of opportunity for vaccine manufacturers in Brazil and other developing countries in the current paradigm transition towards Vaccinology 4.0. We conclude with recommendations for a new governance strategy supporting Brazilian public vaccine manufacturers in international collaborations for a sustainable national vaccine development and production plan by 2030.

Regulatory evolution and challenges from the perspective of public laboratiories vaccine producers in Brazil. / A evolução regulatória e os desafios na perspectiva dos laboratórios públicos produtores de vacinas no Brasil.

The regulation of biological products has evolved rapidly in recent years due to quality issues impacting people's lives and the advent of new technologies, with constant changes in regulations that dictate how a product is registered, produced, and monitored. In the case of vaccines, the responsibility of regulators and manufacturers in guaranteeing quality, safety, and efficacy is even more critical, since vaccines are mostly used in children and healthy patients. In this scenario, manufacturers need to create strategies to keep their products and installations adequate and up-to-date with a fully operational quality system. Meanwhile, regulatory agencies have the role of guaranteeing that products meet the established criteria without compromising the supply of medicines to the population.

A regulamentação para produtos biológicos vem evoluindo rapidamente ao longo dos últimos anos, seja motivada por questões de qualidade com impacto na vida das pessoas, seja pelo advento de novas tecnologias. As mudanças nas regulamentações que ditam como um produto deve ser registrado, produzido e monitorado são constantes. A responsabilidade de reguladores e fabricantes na garantia da qualidade, segurança e eficácia das vacinas torna-se ainda mais crítica, uma vez que essas substâncias são utilizadas, em sua maioria, em crianças e em pacientes saudáveis. Diante desse cenário, fabricantes precisam criar estratégias para manter seus produtos e instalações adequadas e um sistema da qualidade atualizado e operante. Por outro lado, as agências reguladoras têm o papel de garantir que os produtos que estão em uso atendam aos critérios estabelecidos, sem comprometer o fornecimento de medicamentos para a população.

La regulación para productos biológicos ha evolucionado rápidamente a lo largo de los últimos años, sea motivada por cuestiones de calidad con impacto en la vida de las personas, o por el advenimiento de nuevas tecnologías. Los cambios en las regulaciones que dictan como un producto debe ser registrado, producido y monitoreado son constantes. La responsabilidad de reguladores y fabricantes en la garantía de la calidad, seguridad y eficacia de las vacunas se convierte en algo todavía más crítico, ya que estas sustancias se utilizan, en su mayoría, en niños y pacientes saludables. Ante este escenario, los fabricantes necesitan crear estrategias para mantener sus productos e instalaciones de forma adecuada, además de un sistema de calidad actualizado y operativo. Por otro lado, las agencias reguladoras tienen el papel de garantizar que los productos que están en uso atiendan a los criterios establecidos, sin comprometer el suministro de medicamentos para la población.

Sofosbuvir shows a protective effect against vertical transmission of Zika virus and the associated congenital syndrome in rhesus monkeys.

The outbreaks of Zika virus (ZIKV) infection in Brazil, 2015-2016, were associated with severe congenital malformations. Our translational study aimed to test the efficacy of the antiviral agent sofosbuvir (SOF) against vertical transmission of ZIKV and the associated congenital syndrome (CZS), using a rhesus monkey model. Eight pregnant macaques were successfully infected during the organogenesis phase with a Brazilian ZIKV strain; five of them received SOF from two to fifteen days post-infection. Both groups of dams showed ZIKV-associated clinical signals, detectable ZIKV RNA in several specimens, specific anti-ZIKV IgM and IgG antibodies, and maternal neutralizing antibodies. However, malformations occurred only among non-treated dam offspring. Compared to non-treated animals, all SOF-treated dams had a shorter ZIKV viremia and four of five neonates had undetectable ZIKV RNA in blood and tissue samples. These results support further clinical evaluations aiming for the prevention of CZS.

Contemporary human papillomavirus genotyping and correlations to peniscopy, cytology, and histopatology on over 1000 males.

OBJECTIVES: To explore male human papillomavirus (HPV) contemporary genotyping epidemiology and correlations to peniscopy, cytology, and histopatology. METHODS: Medical records of patients who had been submitted to HPV infection screening with genotyping, peniscopy, cytology, and histopathology in a period of 2 years were reviewed. Frequency analysis and correlations between the diagnostic tools were established. RESULTS: Genotype of 1132 men resulted in 69.2% (784) positivity for HPV DNA, 78% classified as high risk of oncogenesis. Co-infections occurred in 429 (54.7%) and the most frequently identified types were HPV-6, HPV-42, and HPV-16, in 133 (17%), 94 (12%), and 86 (11%) patients, respectively. Positive/negative predictive values of peniscopy, cytology, and histopathology were 83/31%, 92/32%, and 87/33%, respectively. As a result, though significant, the correlations between genotype and non-molecular tests were poor. CONCLUSIONS: In the current contemporary representative male cohort, over two thirds are positive for human HPV DNA, 78% of high risk and with over half co-infections. Though significant, its correlation with non-molecular tests is poor and while the positive predictive values of peniscopy, cytology, and histopatology are between 83% and 92%, their negative predictive values are as low as 31% to 33%.

Inadequacies of musculoskeletal medicine curriculum for undergraduate medical students: a cross-sectional study.

BACKGROUND: Musculoskeletal disorders account for up to one in four of general-practice consultations and almost one third of complaints in primary-care clinical practice. However, an insufficient amount of time and importance is given to their teaching in most medical schools. OBJECTIVE: To evaluate the acquisition of musculoskeletal competences in our institution, in order to identify flaws and propose changes to correct and improve the musculoskeletal curriculum. DESIGN AND SETTING: Cross-sectional study conducted in São Paulo, Brazil. METHODS: First to fifth-year medical students were enrolled in a survey using the Freedman and Bernstein musculoskeletal examination, in order to evaluate the acquisition of musculoskeletal competencies. Categorical data were analyzed using the chi-square test. Continuous data were analyzed using one-way analysis of variance (ANOVA). The level of significance was set as P < 0.05. RESULTS: A total of 545 students completed the questionnaire: from year 2, 115/167 (29.6%); from year 3, 118/138 (30.4%); from year 4, 98/130 (25.3%); and from year 5, 57/110 (14.7%). None of the students achieved the pass mark (established as 70%). The level of confidence in performing musculoskeletal examination was very low (3.7 ± 2.2; n = 386) and bore no relationship to the percentage of correct answers in the questionnaire (r = 0.331; 95% confidence interval, CI: 0.239-0.417; P < 0.001). CONCLUSION: Undergraduate teaching is the only exposure most general practitioners have to orthopedic problems. Universities are concerned about the adequacy of the musculoskeletal programs taught in their institutions. Student scores were found to be unsatisfactory in all the topics evaluated.

Inadequacies of musculoskeletal medicine curriculum for undergraduate medical students: a cross-sectional study

ABSTRACT BACKGROUND: Musculoskeletal disorders account for up to one in four of general-practice consultations and almost one third of complaints in primary-care clinical practice. However, an insufficient amount of time and importance is given to their teaching in most medical schools. OBJECTIVE: To evaluate the acquisition of musculoskeletal competences in our institution, in order to identify flaws and propose changes to correct and improve the musculoskeletal curriculum. DESIGN AND SETTING: Cross-sectional study conducted in São Paulo, Brazil. METHODS: First to fifth-year medical students were enrolled in a survey using the Freedman and Bernstein musculoskeletal examination, in order to evaluate the acquisition of musculoskeletal competencies. Categorical data were analyzed using the chi-square test. Continuous data were analyzed using one-way analysis of variance (ANOVA). The level of significance was set as P < 0.05. RESULTS: A total of 545 students completed the questionnaire: from year 2, 115/167 (29.6%); from year 3, 118/138 (30.4%); from year 4, 98/130 (25.3%); and from year 5, 57/110 (14.7%). None of the students achieved the pass mark (established as 70%). The level of confidence in performing musculoskeletal examination was very low (3.7 ± 2.2; n = 386) and bore no relationship to the percentage of correct answers in the questionnaire (r = 0.331; 95% confidence interval, CI: 0.239-0.417; P < 0.001). CONCLUSION: Undergraduate teaching is the only exposure most general practitioners have to orthopedic problems. Universities are concerned about the adequacy of the musculoskeletal programs taught in their institutions. Student scores were found to be unsatisfactory in all the topics evaluated.

Molecular Pharming for low and middle income countries.

Interest in applications and benefits that Molecular Pharming might offer to Low and Middle Income Countries has always been a potent driver for the research discipline, and a major reason why many scientists entered the field. Although enthusiasm remains high, the reality is that such a game-changing innovation would always take longer than traditional uptake of new technology in developed countries, and be complicated by external factors beyond technical feasibility. Excitingly, signs of increasing interest by LMICS in Molecular Pharming are now emerging. Here, three case studies from Thailand, South Africa and Brazil are used to identify some of the key issues when a new investment into Molecular Pharming manufacturing capacity is under consideration. At present, academic research is not necessarily addressing these issues. Only by understanding the concerns, can members of the academic community contribute to helping the development of Molecular Pharming for LMICs by focusing their research efforts appropriately.

A evolução regulatória e os desafios na perspectiva dos laboratórios públicos produtores de vacinas no Brasil / La evolución regulatoria y los desafíos desde la perspectiva de los laboratorios públicos productores de vacunas en Brasil / Regulatory evolution and challenges from the perspective of public laboratiories vaccine producers in Brazil

A regulamentação para produtos biológicos vem evoluindo rapidamente ao longo dos últimos anos, seja motivada por questões de qualidade com impacto na vida das pessoas, seja pelo advento de novas tecnologias. As mudanças nas regulamentações que ditam como um produto deve ser registrado, produzido e monitorado são constantes. A responsabilidade de reguladores e fabricantes na garantia da qualidade, segurança e eficácia das vacinas torna-se ainda mais crítica, uma vez que essas substâncias são utilizadas, em sua maioria, em crianças e em pacientes saudáveis. Diante desse cenário, fabricantes precisam criar estratégias para manter seus produtos e instalações adequadas e um sistema da qualidade atualizado e operante. Por outro lado, as agências reguladoras têm o papel de garantir que os produtos que estão em uso atendam aos critérios estabelecidos, sem comprometer o fornecimento de medicamentos para a população.

La regulación para productos biológicos ha evolucionado rápidamente a lo largo de los últimos años, sea motivada por cuestiones de calidad con impacto en la vida de las personas, o por el advenimiento de nuevas tecnologías. Los cambios en las regulaciones que dictan como un producto debe ser registrado, producido y monitoreado son constantes. La responsabilidad de reguladores y fabricantes en la garantía de la calidad, seguridad y eficacia de las vacunas se convierte en algo todavía más crítico, ya que estas sustancias se utilizan, en su mayoría, en niños y pacientes saludables. Ante este escenario, los fabricantes necesitan crear estrategias para mantener sus productos e instalaciones de forma adecuada, además de un sistema de calidad actualizado y operativo. Por otro lado, las agencias reguladoras tienen el papel de garantizar que los productos que están en uso atiendan a los criterios establecidos, sin comprometer el suministro de medicamentos para la población.

The regulation of biological products has evolved rapidly in recent years due to quality issues impacting people's lives and the advent of new technologies, with constant changes in regulations that dictate how a product is registered, produced, and monitored. In the case of vaccines, the responsibility of regulators and manufacturers in guaranteeing quality, safety, and efficacy is even more critical, since vaccines are mostly used in children and healthy patients. In this scenario, manufacturers need to create strategies to keep their products and installations adequate and up-to-date with a fully operational quality system. Meanwhile, regulatory agencies have the role of guaranteeing that products meet the established criteria without compromising the supply of medicines to the population.

Vaccines for neglected and emerging diseases in Brazil by 2030: the valley of death and opportunities for RD& I in Vaccinology 4. 0 / Vacunas en Brasil para enfermedades emergentes y olvidadas en 2030: el valle de la muerte y oportunidades para RD& I en Vacunología 4. 0 / Vacinas para doenças negligenciadas e emergentes no Brasil até 2030: o vale da morte e oportunidades para PD& I na Vacinologia 4. 0

Abstract: We examine the implications of the very low competitiveness of the Brazilian vaccine RD&I system, which precludes the development of all the important vaccines required by the National Immunization Program (NIP), severely impacting the healthcare of the population. In a country dramatically affected by COVID-19 pandemic and by an exponential increase in emerging and neglected diseases, particularly the poor, these RD&I constraints for vaccines become crucial governance issues. Such constraints are aggravated by a global scenario of limited commercial interest from multinational companies in vaccines for neglected and emerging diseases, which are falling into a "valley of death," with only two vaccines produced in a pipeline of 240 vaccines. We stress that these constraints in the global pipeline are a window of opportunity for vaccine manufacturers in Brazil and other developing countries in the current paradigm transition towards Vaccinology 4.0. We conclude with recommendations for a new governance strategy supporting Brazilian public vaccine manufacturers in international collaborations for a sustainable national vaccine development and production plan by 2030.

Resumen: Examinamos las implicaciones de la muy baja competitividad del sistema brasileño de ID&I de vacunas, que imposibilita el desarrollo de todas las vacunas importantes, requeridas por el Progrma Nacional de Inmunización (PNI), con impactos muy graves en la salud de la población de un país con 200 millones de habitantes. En un país gravemente afectado por la pandemia de COVID-19 y por enfermedades emergentes y olvidadas que afectan particularmente a los pobres, estas restricciones del ID&I para vacunas es, de hecho, un asunto crucial de gobierno. Estas limitaciones locales se han visto agravadas por un escenario global de interés comercial limitado, por parte de las compañías multinacionales, en vacunas para enfermedades emergentes y olvidadas, que están cayendo en un "valle de la muerte", con solamente dos vacunas producidas a nivel global frente a 240 vacunas. Identificamos en estas limitaciones globales una ventana de oportunidad para los fabricantes de vacunas en Brasil y otros países en desarrollo dentro del paradigma actual de transición hacia la Vacunología 4.0. Concluimos con recomendaciones de una nueva estrategia de gobierno que apoye a los fabricantes brasileños de vacunas públicas en colaboraciones internacionales para el plan nacional de desarrollo y producción sostenible de vacunas en 2030.

Resumo: Examinamos as implicações da competitividade tão baixa do sistema brasileiro de pesquisa, desenvolvimento e inovação (PD&I) de vacinas, que impede o desenvolvimento de todas as vacinas importantes requeridas pelo Programa Nacional de Imunizações (PNI), prejudicando gravemente a saúde da população. Em um país seriamente afetado pela pandemia de COVID-19 e por um aumento exponencial de doenças emergentes e negligenciadas, principalmente entre os brasileiros pobres, essas restrições de PD&I quanto às vacinas tornam-se questões cruciais de governança. Essas restrições são agravadas por um cenário global de interesse comercial limitado por parte das empresas multinacionais de vacinas para doenças negligenciadas e emergentes, que estão caindo em um "vale da morte", com apenas duas vacinas produzidas em um pipeline de 240 vacinas. Ressaltamos que essas restrições na produção global constituem uma janela de oportunidade para os fabricantes de vacinas no Brasil e em outros países em desenvolvimento na atual transição de paradigma para a Vacinologia 4.0. Concluímos com recomendações para uma nova estratégia de governança em suporte aos fabricantes públicos de vacinas no Brasil em colaborações internacionais para um plano nacional de desenvolvimento e produção de vacinas que seja sustentável até 2030.

A evolução regulatória e os desafios na perspectiva dos laboratórios públicos produtores de vacinas no Brasil / La evolución regulatoria y los desafíos desde la perspectiva de los laboratorios públicos productores de vacunas en Brasil / Regulatory evolution and challenges from the perspective of public laboratiories vaccine producers in Brazil

A regulamentação para produtos biológicos vem evoluindo rapidamente ao longo dos últimos anos, seja motivada por questões de qualidade com impacto na vida das pessoas, seja pelo advento de novas tecnologias. As mudanças nas regulamentações que ditam como um produto deve ser registrado, produzido e monitorado são constantes. A responsabilidade de reguladores e fabricantes na garantia da qualidade, segurança e eficácia das vacinas torna-se ainda mais crítica, uma vez que essas substâncias são utilizadas, em sua maioria, em crianças e em pacientes saudáveis. Diante desse cenário, fabricantes precisam criar estratégias para manter seus produtos e instalações adequadas e um sistema da qualidade atualizado e operante. Por outro lado, as agências reguladoras têm o papel de garantir que os produtos que estão em uso atendam aos critérios estabelecidos, sem comprometer o fornecimento de medicamentos para a população.

La regulación para productos biológicos ha evolucionado rápidamente a lo largo de los últimos años, sea motivada por cuestiones de calidad con impacto en la vida de las personas, o por el advenimiento de nuevas tecnologías. Los cambios en las regulaciones que dictan como un producto debe ser registrado, producido y monitoreado son constantes. La responsabilidad de reguladores y fabricantes en la garantía de la calidad, seguridad y eficacia de las vacunas se convierte en algo todavía más crítico, ya que estas sustancias se utilizan, en su mayoría, en niños y pacientes saludables. Ante este escenario, los fabricantes necesitan crear estrategias para mantener sus productos e instalaciones de forma adecuada, además de un sistema de calidad actualizado y operativo. Por otro lado, las agencias reguladoras tienen el papel de garantizar que los productos que están en uso atiendan a los criterios establecidos, sin comprometer el suministro de medicamentos para la población.

The regulation of biological products has evolved rapidly in recent years due to quality issues impacting people's lives and the advent of new technologies, with constant changes in regulations that dictate how a product is registered, produced, and monitored. In the case of vaccines, the responsibility of regulators and manufacturers in guaranteeing quality, safety, and efficacy is even more critical, since vaccines are mostly used in children and healthy patients. In this scenario, manufacturers need to create strategies to keep their products and installations adequate and up-to-date with a fully operational quality system. Meanwhile, regulatory agencies have the role of guaranteeing that products meet the established criteria without compromising the supply of medicines to the population.

Duration of post-vaccination humoral immunity against yellow fever in children.

INTRODUCTION: Vaccination is the most important measure for prevention and control of yellow fever. It is recommended by the World Health Organization (WHO) for residents of endemic areas and travelers to risk areas. In 2013, the WHO discontinued the recommendation of booster doses every 10 years, indicating a single dose as sufficient for lifelong protection. OBJECTIVE: Considering the lower immune response to YF vaccine in children compared to adults, this study was set out to assess the duration of immunity to YF in children vaccinated in the first two years of life. METHODS: This cross-sectional study involved children aged 9 months to 12 years with accessible vaccination records recruited in primary care units from a metropolitan area in Southeast Brazil. The serologic status (negative, indeterminate and positive), and geometric mean titers (GMT, inverse dilution) of neutralizing antibodies against YF obtained by Plaque Reduction Neutralization Test was assessed across categories of time after YF vaccination. The strength of association of seropositivity with time was assessed by the odds ratio (OR) taking recent vaccination (1-6 months) as reference. RESULTS: A total of 824 children recruited from August 2010 to July 2011were tested. The proportion of seropositivity (95% C.I.) and GMT (95% C.I.) dropped markedly across time periods: from 86.7% (80.5-91.4%), GMT 47.9 (38.3-59.9) in newly vaccinated to 59.0% (49.7-67.8%), GMT 14.8 (11.6-19.1) and 42.2% (33.8-51.0), GMT 8.6 (7.1-12.1), respectively in the subgroups vaccinated 31-72 months and 73-100 months before. CONCLUSIONS: Analogous to previous findings in adults, these data support the need for revaccination of children living in areas with yellow fever virus circulation in humans or in other primates. The data also supported the change of a booster dose to 4 years of age for those primarily vaccinated for yellow fever in the first two years of life.

Short-Lived Immunity After 17DD Yellow Fever Single Dose Indicates That Booster Vaccination May Be Required to Guarantee Protective Immunity in Children.

The Yellow Fever (YF) vaccination is recommended for people living in endemic areas and represents the most effective strategy to reduce the risk of infection. Previous studies have warned that booster regimens should be considered to guarantee the long-term persistence of 17DD-YF-specific memory components in adults living in areas with YF-virus circulation. Considering the lower seroconversion rates observed in children (9-12 months of age) as compared to adults, this study was designed in order to access the duration of immunity in single-dose vaccinated children in a 10-years cross-sectional time-span. The levels of neutralizing antibodies (PRNT) and the phenotypic/functional memory status of T and B-cells were measured at a baseline, 30-45 days, 1, 2, 4, 7, and 10 years following primary vaccination. The results revealed that a single dose induced 85% of seropositivity at 30-45 days and a progressive time-dependent decrease was observed as early as 2 years and declines toward critical values (below 60%) at time-spans of ≥4-years. Moreover, short-lived YF-specific cellular immunity, mediated by memory T and B-cells was also observed after 4-years. Predicted probability and resultant memory analysis emphasize that correlates of protection (PRNT; effector memory CD8+ T-cells; non-classical memory B-cells) wane to critical values within ≥4-years after primary vaccination. Together, these results clearly demonstrate the decline of 17DD-YF-specific memory response along time in children primarily vaccinated at 9-12 months of age and support the need of booster regimen to guarantee the long-term persistence of memory components for children living in areas with high risk of YF transmission.

Purification of yellow fever virus produced in Vero cells for inactivated vaccine manufacture.

Yellow fever (YF) is a high-lethality viral disease, endemic in tropical regions of South America and Africa, with a population of over 900 million people under risk. A highly effective attenuated vaccine, produced in embryonated eggs, has been used for about 80 years. However, egg-based production limits manufacturing capacity, and vaccine shortage led to the emergency use of a fractional dose (1/5) by the WHO in an outbreak in Africa in 2016 and by Brazilian authorities during an outbreak in 2018. In addition, rare but fatal adverse events of this vaccine have been reported since 2001. These two aspects make clear the need for the development of a new vaccine. In an effort to develop an inactivated YF vaccine, Bio-Manguinhos/FIOCRUZ started developing a new vaccine based on the production of the attenuated 17DD virus in serum-free conditions in Vero cells propagated in bioreactors, followed by chromatography-based purification and ß-propiolactone inactivation. Virus purification was studied in this work. Capture was performed using an anion-exchange membrane adsorber (Sartobind® Q), resulting in a virus recovery of 80.2 ±â€¯4.8% and a residual DNA level of 1.3 ±â€¯1.6 ng/dose, thus in accordance with the recommendations of the WHO (<10 ng/dose). However, the level of host cell proteins (HCP) was still high for a human vaccine, so a second chromatography step was developed based on a multimodal resin (Capto™ Core 700). This step resulted in a virus recovery of 65.7 ±â€¯4.8% and decreased HCP levels to 345 ±â€¯25 ppm. The overall virus recovery in these chromatography steps was 52.7%. SDS-PAGE of the purified sample showed a band with molecular mass of 56 kDa, thus consistent with the virus envelope protein (E) and corresponding to 96.7% of identified proteins. A Western blot stained with an antibody against the E protein showed a single band, confirming the identity of the sample.

Detection of post-vaccination enhanced dengue virus infection in macaques: An improved model for early assessment of dengue vaccines.

The need for improved dengue vaccines remains since the only licensed vaccine, Dengvaxia, shows variable efficacy depending on the infecting dengue virus (DENV) type, and increases the risk of hospitalization for severe dengue in children not exposed to DENV before vaccination. Here, we developed a tetravalent dengue purified and inactivated vaccine (DPIV) candidate and characterized, in rhesus macaques, its immunogenicity and efficacy to control DENV infection by analyzing, after challenge, both viral replication and changes in biological markers associated with dengue in humans. Although DPIV elicited cross-type and long-lasting DENV-neutralizing antibody responses, it failed to control DENV infection. Increased levels of viremia/RNAemia (correlating with serum capacity at enhancing DENV infection in vitro), AST, IL-10, IL-18 and IFN-γ, and decreased levels of IL-12 were detected in some vaccinated compared to non-vaccinated monkeys, indicating the vaccination may have triggered antibody-dependent enhancement of DENV infection. The dengue macaque model has been considered imperfect due to the lack of DENV-associated clinical signs. However, here we show that post-vaccination enhanced DENV infection can be detected in this model when integrating several parameters, including characterization of DENV-enhancing antibodies, viremia/RNAemia, and biomarkers relevant to dengue in humans. This improved dengue macaque model may be crucial for early assessment of efficacy and safety of future dengue vaccines.